Combat

Unlike Palkia or Giratina, Dialga has very little in the way of spell-like abilities. But it doesn't need them. Dialga is the embodiment of time, and therefore, it has virtually all of the abilities of a time walker - only to a ludicrous degree. It also carries a couple of highly dangerous time-bending abilities.

Breath Weapon (Su): Dialga can breathe an 80' line of temporal fire once every 1d4+1 rounds. This deals 2d4 force damage per hit die, with a Ref save (Constitution-based) for half damage. Failing the save by 5 or more renders a victim paralyzed for 1d4 rounds. The sample Dialga deals 40d4 damage with a DC of 30. This is a [Dragon] effect.

Roar of Time (Su): Dialga's signature move, this attack inflicts tremendous damage at the price of utter exhaustion. As a full-round action, Dialga may let loose a mighty roar that rends the very fabric of time, dealing 4d12 typeless damage per Hit Dice Dialga has to everything within 60 feet of it. Foes may make a Reflex save to halve the damage. After using Roar of Time, Dialga is so exhausted that it skips its next turn, as if dazed. On its turn after that, Dialga is exhausted, and on the turn after that, it's fatigued. Dialga loses its Flow of Time bonuses for the entirety of these three rounds (plus for one round afterwards), and also loses the use of its Annul, Temporal Strike, Delaying Strike, Greater Delaying Strike, and Moment Stop abilities. On the fourth turn after a Roar of Time attack (one turn after the fatigue goes away), Dialga has recovered from its massive expenditure of power, regaining all of the abilities it lost; however, Dialga can still only use Roar of Time once every two minutes. The sample Dialga does 80d12 damage with its Roar of Time, and the save DC is 24; the save DC for Roar of Time is Charisma-based (enhanced by Ability Focus). This is a [Dragon] effect.

Roar of Time is a very dangerous attack; 80d12 is more damage than any 20th-level character can handle, especially since there's no way to resist it (except for a successful Reflex save). Try not to let the whole party be within 60 feet of Dialga at any time, or you're going to be TPK'd. If you can somehow bait Dialga into only smiting one of your party (or, better yet, a summoned creature) with Roar of Time, though, you'll be okay. Dialga's not that stupid, though, and will try to make sure that when it uses Roar of Time, a huge portion of its opposition will be obliterated. After all, it's quite vulnerable during the first eighth of the cooldown time.

Time Snap (Sp): Dialga's other signature move, and one that isn't seen very often. As a 2-round action that requires it to sacrifice hp equal to 25% of its maximum upon initiation, Dialga can attempt to sink even deeper into the flow of time to drastically enhance its combat effectiveness. Dialga must concentrate intensely on this move to make it work properly, so anything that could interrupt the casting of a spell can cause this move to fail. (Dialga can just try again, but it must lose hp equal to 25% of its maximum each time, and cannot attempt it at all if it is at less than 25% of its maximum hp.) This is the equivalent of a 9th-level spell. If Dialga manages to perform this ability successfully, then at the end of the second round, it will gain a +12 enhancement bonus to its natural armor and each of its ability scores that lasts for the remainder of the encounter. Dialga cannot attempt to perform this move if it is not in the flow of time (which means that it's unusable for 4 rounds after a Roar of Time.

Aura Sphere (Su): Once per minute, Dialga can briefly expand its aura. All within 30' are automatically struck and take 1d6+1 Force damage per level; however, this is a [Fighting] effect. There is no way at all to avoid this effect, although the rare resistance or immunity to Force damage can still apply to the damage. In a Contest, this always gets a minimum of one point.

Earth Power (Sp): One of Dialga's few spell-like abilities, this is a flame strike from below rather than from above. Instead of divine energy, half of the damage is a [Ground] effect. Dialga's caster level is equal to its Hit Dice (20th). Save DC is Charisma-based. Dialga may use earth power 5 times per day (once per 4 Hit Dice).

Flash Cannon (Sp): This is an empowered fireball with the damage cap removed. Instead of fire damage, it deals light damage, and is considered a [Metal] effect. Dialga's caster level is equal to its Hit Dice (20th). Save DC is Charisma-based. Dialga may use flash cannon 5 times per day (once per 4 Hit Dice).

Flow of Time (Ex): Dialga and time are practically synonymous. Dialga is perpetually in a flow of time state, as a time walker, level equal to its HD. Dialga never exits the flow of time unless it uses Roar of Time, which forces it out of the flow of time for 4 rounds after being used. Due to the Flow of Time, Dexterity and Wisdom scores are 8 more than their equivalents in its two counterparts (reflected in its statistics block; Dialga's 23-point mental score is Wisdom, which is boosted by 8 by its Flow of Time ability), and it may reroll one die roll per round.

At 30 HD, Dialga's Flow of Time bonuses to Dexterity and Wisdom become +10 each, and it makes the second roll of any dice it rerolls with a +10 competence bonus.

Annul (Ex): Dialga knows how to channel the healing powers that time blesses it with to an amazing degree. At the end of any round in which Dialga has not used its reroll for the round, it heals a number of hit points equal to 5 + its Wisdom modifier. This is in addition to its fast healing. The sample Dialga heals 15 hp with Anull.

Fast Healing (Ex): Dialga's control over the flow of time continuously repairs its wounds. Dialga has fast healing equal to its HD/3. (The sample Dialga has fast healing/6.)

Fast Movement (Ex): Dialga has it within its power to seemingly slow down time around it, yet still remain going at the same speed. Dialga has a +10 ft. enhancement bonus to its speed for every three of its Hit Die. The sample Dialga has a +60-ft. enhancement bonus to its speed. (Unlike Palkia and Giratina, though, Dialga is unable to fly.)

Temporal Strike (Ex): Dialga has the ability to make one attack it makes in any given round a temporal strike by slashing through the temporal existence of a creature instead of its physical existence. This attack has a distortion bonus equal to half Dialga's Hit Die (rounded down), applied to both attack rolls and damage rolls. A temporal strike ignores all effects that grant miss chances, such as concealment. Additionally, on a successful temporal strike, the target becomes fatigued for a number of rounds equal to the distortion bonus. If a fatigued character is struck by Dialga's temporal strike ability, then they do not become exhausted, and the duration of the fatigue overlaps. This works in all respects like the equivalent ability of a time walker. The sample Dialga has a +10 distortion bonus to temporal strikes. Dialga can make a temporal strike, delaying strike, and greater delaying strike all in the same round; however, only one of each of these three kinds of attacks can be made per round, and they must each augment a different attack in Dialga's full attack routine.

Delay: Time is something that is rarely noticed, until you lose some of it. Dialga has the ability to make a single attack per round into a delaying strike. If this attack lands, then no damage is dealt; instead, the target of the attack drops one place in order of initiative. Dialga can make a temporal strike, delaying strike, and greater delaying strike all in the same round; however, only one of each of these three kinds of attacks can be made per round, and they must each augment a different attack in Dialga's full attack routine. Because it deals no damage, the delaying strike cannot be an awesome blow.

Time Sync (Ex): Time is something that nothing can hold off, no matter how resolute it may be. Dialga can make one attack each round as a melee touch attack. This attack can also be a temporal strike, delaying strike, or greater delaying strike.

Walk the Aeons (Ex): Dialga has it within its power to comprehend time on many different levels, allowing it to move with precision that few can comprehend. Dialga adds its Wisdom bonus as an insight bonus to its AC.

Moment Stop: Dialga may not have the quickest reactions, but it can take steps in between the passage of one moment and the next. Dialga has the ability to take one additional 5 ft. free step, move its speed, or move four times its speed as an immediate action that does not actually count against the total immediate actions or swift actions it can take in a round. If this ability is used after an opponent has moved to a square where they threaten Dialga, but before the opponent makes an attack, then the opponent counts as having used his move action for the turn unless he has the Spring Attack feat and his total movement doesn't exceed his total speed. Dialga can only use a given variant of this ability once every 1d4 rounds, and can only use one moment stop ability per round.

Greater Delay: Dialga can rip apart a being's timeline in and of itself, making them forget that time is even flowing for long moments. Dialga has the ability to make a single attack per round into a greater delaying strike. If this attack lands, then no damage is dealt; instead, the target must make a Will save (DC 10 + half Dialga's Hit Die + Dialga's Wisdom modifier) or skip their next turn. Dialga can make a temporal strike, delaying strike, and greater delaying strike all in the same round; however, only one of each of these three kinds of attacks can be made per round, and they must each augment a different attack in Dialga's full attack routine. Because it deals no damage, the greater delaying strike cannot be an awesome blow.

Renewal (Ex): Dialga has an extremely tight grip on the reins of time (well, it doesn't have opposable thumbs, but... never mind...) Once every 5d4 rounds, as a free action, it may focus and release in the blink of an eye, regaining a number of hit points equal to its Wisdom modifier × its Hit Dice. Dialga may take this free action and heal itself at any point - even a mere instant after it's taken enough damage to fall unconscious or die. The sample Dialga regains 200 hp from Renewal.

Foresight (Ex): Dialga is so incredibly aware of the flow of time that it can comprehend moments and events before they even come to take place. Dialga may act normally in a surprise round, no matter the circumstances, and is never caught flat-footed. It also receives its Wisdom modifier as an insight bonus to attack rolls and saving throws.

Time Travel (Su): Dialga has incredible powers of time. It can cast a Gate (travel version) ability as a Supernatural ability at will, except it links to the same place and plane, in a different time period. It can also cast Foresight (the spell, not the class feature) at will, and always has an additional standard action available, much like the old Haste granted.

Pressure (Su): Anyone who makes an attack against Dialga must make a Will save vs. DC 22 after the attack is resolved. If they fail, they become Fatigued for 3 rounds. If already fatigued, they become Exhausted instead. This does not stack with fatigue from a Temporal Strike; it overlaps. This applies to any harmful ability, whether it be a regular attack, a spell, a supernatural ability, or anything else that targets Dialga or includes it in the area of effect. The save DC is Charisma-based.

For reasons that will never be explained, Cranidos, Rampardos, Reshiram, Zekrom, White Kyurem, Black Kyurem, and some specimens of Pinsir are immune to this. Scholars and loremasters, if they even know of this, would be puzzled for many years.

Advancement

Aside from the improvements mentioned above, Dialga starts to gain spell-like abilities as it increases its Hit Die:

Time Hop, gained at 23 HD, has 30 points available + 10 per Hit Die beyond 23rd per day.

Time Stop, gained at 26 HD, may be used once per day plus 1 additional time per day for every 4 Hit Dice beyond 26th.

Turn Back the Pendulum, gained at 32 HD, may be used once per day plus 1 additional time per day for every 6 Hit Dice beyond 32nd.